(1) Field of the Invention
The present invention relates generally to a post structure, and in particular to a multi-part post system including a ground anchor for vertical insertion into the earth, and a post that is mounted onto an above-ground portion of the anchor. The invention also contemplates use of the ground anchor without the post.
(2) Description of the Prior Art
Posts such as fence posts, mailbox posts, and the like, are conventionally mounted vertically above the surface of the ground by inserting the lower end of the post into a prepared hole. After the post has been vertically aligned, e.g., by placing a spirit level along the side of the post, the area around the post is filled with dirt or a concrete mix. This procedure, while effective, is time consuming. In addition, the lower end of the post will rot over time due to exposure to moisture in the soil. Also, removal or replacement of the post, particularly if the lower end is set in concrete, can be difficult.
Alternative post mounting procedures use devices known as ground anchors, which are described in various prior art patents, including the following:
U.S. Pat. No. Inventor(s) 3,011,597 Galloway et al. 3,952,523 Gale 4,593,872 Svensson 4,803,812 Alexander, Sr. 4,863,137 Cockman 4,923,165 Cockman 5,011,107 Reece
Ground anchors of the type used to mount posts are basically comprised of a rod or staff having a lower end that is inserted into the ground, and an upper end to which the lower end of a post is secured. While the lower end of the rod can be simply driven into the earth, many ground anchors include an auger blade around the lower end of the rod, so that the rod can be screwed into the earth to provide a more stable anchor.
These ground anchors, have some advantages over conventional post mounting, in particular, ease of post installation, and post removal or replacement. However, correct installation of post anchors is difficult, since the anchor must be installed vertically in order for the post to be vertical. While specialized, bulky devices are available in the prior art to facilitate vertical insertion of ground anchors, their cost to the average homeowner is prohibitive. Vertical insertion of prior art anchors either manually or with hand operated power tools has not been possible.
An additional problem with prior art ground anchors is due to the fact that the connection between the post and the ground anchor is only between the extreme lower end of the post and the extreme upper end of the anchor. For example, most prior art ground anchors include a horizontal plate at their upper end with spaced, upwardly projecting side plates. The lower post end is positioned on the horizontal plate and attached to the anchor with nails or screws that extend through the side plates and into the post. As a result, the post can be easily broken away from, or shifted in relation to, the ground anchor.
Prior art ground anchors, and post attached thereto, are often unstable. That is, the ground anchor, even if initially installed vertically, tends to shift or lean to a non-vertical alignment when even moderate lateral forces are placed against the post, due to the large moment arm of the post, and the small diameter of the rod which provides only a limited contact between the rod and adjacent earth. Avoidance of this problem has not been addressed in the past, however, due to the difficulty in inserting large diameter rods into the earth.
A system having the advantages of known ground anchors that also provided for ease of vertical anchor installation, improved attachment between the post and anchor, time and cost savings for the end consumer, prolonged fence life, and a high level of stability, would be of significant commercial value.